Structural basis of RNA-dependent recruitment of glutamine to the genetic code.

Hiroyuki Oshikane (1) , Kelly Sheppard (2) , Shuya Fukai (1) , Yuko Nakamura (1) , Ryuichiro Ishitani (1) , Tomoyuki Numata (1) , R Lynn Sherrer (2) , Liang Feng (2) , Emmanuelle Schmitt (3) , Michel Panvert (3) , Sylvain Blanquet (3) , Yves Mechulam (3) , Dieter Söll (2) , Osamu Nureki (1)

1 DBI - Department of biological information-Tokyo Institute of Technology
2 DMBB - Department of Molecular Biophysics and Biochemistry-Yale
3 BIOC - Laboratoire de Biochimie de l'Ecole polytechnique

Glutaminyl-transfer RNA (Gln-tRNA(Gln)) in archaea is synthesized in a pretranslational amidation of misacylated Glu-tRNA(Gln) by the heterodimeric Glu-tRNA(Gln) amidotransferase GatDE. Here we report the crystal structure of the Methanothermobacter thermautotrophicus GatDE complexed to tRNA(Gln) at 3.15 angstroms resolution. Biochemical analysis of GatDE and of tRNA(Gln) mutants characterized the catalytic centers for the enzyme's three reactions (glutaminase, kinase, and amidotransferase activity). A 40 angstrom-long channel for ammonia transport connects the active sites in GatD and GatE. tRNA(Gln) recognition by indirect readout based on shape complementarity of the D loop suggests an early anticodon-independent RNA-based mechanism for adding glutamine to the genetic code.

Domaines: Biochimie, Biologie Moléculaire

Hiroyuki Oshikane, Kelly Sheppard, Shuya Fukai, Yuko Nakamura, Ryuichiro Ishitani, et al.. Structural basis of RNA-dependent recruitment of glutamine to the genetic code.. Science, 2006, 312 (5782), pp.1950-4. ⟨10.1126/science.1128470⟩. ⟨hal-00502072⟩